The present invention relates in general to an apparatus and method for processing wireless telephone call messages and in particular to an apparatus and method for processing an embedded message at a mobile station which includes a subscriber identity module.
In order to offer wireless telephone subscribers increased coverage and functionality, many otherwise incompatible wireless systems are converging. For example, the convergence of TIA/EIA-136 and Global System for Mobile Communication (GSM) technologies is taking place through the use of the GSM GPRS protocol and through network nodes in TIA/EIA-136 networks. Multi-mode mobile stations may be used that are able to function on either a TIA/EIA-136 network or on a GSM network. When either the GSM GPRS protocol stack is used by a TIA/EIA-136 mobile station to obtain packet services, or when a TIA/EIA-136 subscriber (as identified by his subscriber identity module or SIM card) is roaming in a GSM network, it is necessary to deliver native TIA/EIA-136 teleservice messages to the mobile station.
Providing such service to the mobile station is problematic because a non-GSM subscriber (e.g., a TIA/EIA-136 subscriber as identified by his SIM card) could be using either a GSM mobile station or a non-GSM mobile station. Further, some of the non-GSM teleservices that are to be delivered to the subscriber may require processing by the mobile station. For example, a non-GSM teleservices may require processing power available in the mobile station, but not available in the SIM card.
In one aspect, the invention is directed to a method for processing an embedded message at a mobile station. The mobile station includes a subscriber identity module. The mobile station receives an encapsulating message which includes an embedded message. The mobile station then determines if a protocol identifier included in the encapsulating message is a predetermined protocol identifier. If the protocol identifier is the predetermined protocol identifier, the mobile station transfers the encapsulating message to the subscriber identity module. The subscriber identity module then determines if the particular protocol identified by the protocol identifier is supported by the subscriber identity module. If the particular protocol is supported by the subscriber identity module, the subscriber identity module extracts the embedded message from the encapsulating message and process the embedded message.
In another aspect, the invention is directed to a method for processing an embedded message at a mobile station. The mobile station includes a subscriber identity module. The mobile station receives an encapsulating message which includes a protocol identifier, a protocol discriminator, a subscriber identity module escape flag, and the embedded message. The mobile station determines if the protocol discriminator is indicative of a protocol supported by the mobile station. If the protocol discriminator is indicative of a protocol supported by the mobile station, the mobile station determines if the protocol identifier identifies a predetermined protocol. If the protocol identifier identifies the predetermined protocol, the mobile station determines if the subscriber identity module escape flag indicates a desire to transfer the encapsulating message to the subscriber identity module. If the subscriber identity module escape flag does not indicate a desire to transfer the encapsulating message to the subscriber identity module, the mobile station extracts and processes the embedded message.
In one embodiment, the mobile station transfers the encapsulating message to the subscriber identity module if the protocol discriminator is indicative of a protocol not supported by the mobile station. The subscriber identity module then determines if the particular protocol identified by the protocol identifier is supported by the subscriber identity module. If the particular protocol is supported by the subscriber identity module, the subscriber identity module extracts and processes the embedded message. In one embodiment, the mobile station transfers the encapsulating message to the subscriber identity module if the subscriber identity module escape flag indicates a desire to transfer the encapsulating message to the subscriber identity module. The subscriber identity module then determines if the particular protocol identified by the protocol identifier is supported by the subscriber identity module. If the particular protocol is supported by the subscriber identity module the subscriber identity module extracts and processes the embedded message.